Brain Matters

The problem with popular science writing is also often what makes it popular in the first place: it makes you think you know more than you do. Or rather it makes you think that scientists—and, by extension, that grasping, grand thing we call the sciences—know more than they do.

This is not necessarily a bad thing. It is, for example, fairly obvious why someone would prefer not to pick up a book about, say, the brain, only to find out how little we know about the brain. There’s no need to dwell on what we don’t know, we say to ourselves, and it’s not relevant to what we do know.

Neuroscientist David Eagleman, in his new book Incognito, certainly says enough about the brain’s inner workings to sustain anyone with the hankering for this kind of knowledge. In Eagleman’s entertaining, only occasionally cloying account, our understanding of this remarkable organ has made enormous progress over the past decades. We have more information than ever about the vast network of competing centers in the brain, from the amygdala to the ventromedial prefrontal cortex—words that, at the very least, make one feel smarter.

We know, roughly speaking, the aspects of thought and behavior for which the brain’s various regions are responsible, and we have a rapidly expanding sense of how minor alterations to any one of them can seriously affect the whole. This influx of knowledge is due, in part, to technological advances. MRI machines are capable of yielding real-time snapshots of brain activity, and a pharmacopoeia of specially tailored drugs is available to modulate brain chemistry. A broader movement in neuroscience is also in play here, one characterized by a resurgent confidence in determining a wholly material basis for the mind’s mysteries.

If this movement has been a boon for brain science, however, it has also shown how little we know about ourselves. What makes Eagleman’s book unique, particularly in the realm of popular science writing, is the attention it gives to this interplay between the knowns and unknowns of neuroscience. He writes first of how our senses are wholly constructed by the wiring of the brain. What seems “real” to us is really the product of an automated system of interconnected neurons, trained to mold whatever sensory input we have at our disposal into a coherent story. Through a smattering of anecdotes, psychological studies, and biological explanations, Eagleman goes on to show how the higher-order aspects of the brain’s activity—consciousness, thinking, feeling, believing—are similarly constructed. The book is a gripping and demystifying assault on the reliability of our senses, the coherence of our impulses, and the agency we ascribe to our decision-making. In this way, Incognito exposes that easily elided paradox of science: the more we learn, the less we know.

These newfound complexities of the brain have profound consequences for our conception of the self. In Eagleman’s view, they dismantle it. The story he tells runs the gamut from the absurd—the tiny tumor, properly positioned, that turns a loving husband into a homicidal maniac—to the countless daily tasks that are accomplished far before “we” are aware of them. But in this telling, the otherwise sad claim of biology—that so much of who we are and how we act is nothing more than a function of grey matter—becomes an occasion for awe. It is awesome for the answers it provides, and for the questions it raises. Eagleman’s openness to the questions—not just the biological ones, but also the philosophical, psychological, and sociological ones—bespeaks a humility essential to such a complex endeavor. As he writes, sampling a well-worn joke, “if our brains were simple enough to be understood, we wouldn’t be smart enough to understand them.”

What we can do (with what little we have) is legislate. If human behavior really is inseparable from biology, how can one justify a system in which blameworthiness is determined by dated laws that presuppose free will, that effectively treat recidivism as a choice to be punished, that divorce rehabilitation from the real burden of brain chemistry? Eagleman, who directs both the Laboratory for Perception and Action and the Initiative on Neuroscience and Law at the Baylor College of Medicine, closes his book with a convincing case for social policy founded on sound neuroscience. The practical implementation of such a program is, of course, fraught with danger. Biological explanations for crime do not excuse criminals; they also do not justify invasive chemical rehabilitation. They do, however, invite a different way of thinking about human agency, one that might inform the way we punish human agents. We may not be reducible to our biology, but we are certainly tied to it.

Ultimately, the problem of living with other people is the problem of living with ourselves. The brilliant irony is that the brain is both the means and the end of the effort to solve this problem. If Eagleman’s book is any indication, we have far to go in this endeavor, but it is well worth the trip. And we can, along the way, console ourselves with the humbling reality that our brains, grey lumps though they may be, know so much more than we do.